D-2.3 Auto “TURNOFF” (Automatic Shutdown)
D-2.4 Light (Front Panel button)
The AMPTEC 620UK Ohmmeter has an LCD Display light switch to turn LCD display lights. If the 620UK
Ohmmeter user is in a dim/poor ambient light environment and viewing the LCD display is difficult press and
hold the front panel switch labeled “LIGHT”. The 620UK Ohmmeter LCD display will be lit and viewable in
dim or dark ambient light conditions, as long as the user holds down the “LIGHT” button (assuming good
batteries). If you press the Amptec 620UK ohmmeter front panel “LIGHT” switch and the LCD display light
does not come on it probably indicates dead batteries or a repair is in order, refer battery replacement or any
repairs to authorised personnel.
D-2.2 Main Power Switch (Front Panel ON/OFF Button)
The main power switch for the AMPTEC 620UK Explosive Safety Ohmmeter is a mo-mentary hold-down
switch that needs to be
held down for approx. 2 seconds to turn “ON”.
This required momentary “hold
down” routine (for 1 to 2 seconds) helps avoid accidental “Power On” whilst the AMPTEC 620UK Ohmmeter
is riding around inside its carrying case. When first pressed and held, (the power switch ) the instrument should
turn “ON” (i.e. the LCD Digital Display comes on), if the switch is pressed again the unit will turn “OFF”. The
main power switch is covered with a silicon rubber boot to provide added water/dust resistance in harsh
environments.
D-2.5 Resistance Range Selection
The AMPTEC RESEARCH 620UK Explosive Safety ohmmeter is fitted with seven resistance ranges. The
lowest resistance range ( 2.0 Ohm ) provides resistance measurement capability from zero ohms up to the level
of
i.9999
Ohms Fullscale. The AMPTEC 620UK resistance range is selected by rotating the front panel
resistance range selection knob to the desired resistance range. The AMPTEC 620UK Explosive Safety
Ohmmeter resistance range selection continues in decades from 2.0 ohms, 20 Ohms, 200 Ohms, 2.0 K Ohms,
20 K Ohms, 200 K Ohms, 2.0 Megohms. If the level of resistance to be measured is not known the AMPTEC
620UK user should select the highest range (2.0 MegOhm Range) and continue down ranging until the user gets
the optimal measurement for the unit’s 4 ½ digit display.
10
The AMPTEC 620UK Explosive Safety Ohmmeter conserves battery power (4 ea. AA batteries - see Section B
for exact type/brand allowed) by turning itself off automatic-ally
after
2
0 minutes
of continual use (i.e. without
a change in range). The AMPTEC 620UK Explosive Safety Ohmmeter operator may simply press the main
power (mo-mentary) switch to turn the unit back “ON” for ten more minutes. The operator does not have to
worry about warm-up time associated with turning the unit back “ON” if it automatically goes “OFF” (i.e. into
“Auto Shutdown mode”). The AMPTEC 620UK Safety Ohmmeter operator may also simply make a range
change and return (i.e.
either
flip the range switch up and back/return
or
press and temporarily hold the main
power switch on again). This will keep the AMPTEC 620UK ohmmeter operating contin-uously for 10 more
minutes. The benefit of conserving battery power far outweighs the second or two it takes to reset the AMPTEC
620UK's “Power Off” timer.
